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Prism
Kinds of Prism Selected AbstractsThe geography of climate change: implications for conservation biogeographyDIVERSITY AND DISTRIBUTIONS, Issue 3 2010D. D. Ackerly Abstract Aim, Climate change poses significant threats to biodiversity, including impacts on species distributions, abundance and ecological interactions. At a landscape scale, these impacts, and biotic responses such as adaptation and migration, will be mediated by spatial heterogeneity in climate and climate change. We examine several aspects of the geography of climate change and their significance for biodiversity conservation. Location, California and Nevada, USA. Methods, Using current climate surfaces (PRISM) and two scenarios of future climate (A1b, 2070,2099, warmer-drier and warmer-wetter), we mapped disappearing, declining, expanding and novel climates, and the velocity and direction of climate change in California and Nevada. We also examined fine-scale spatial heterogeneity in protected areas of the San Francisco Bay Area in relation to reserve size, topographic complexity and distance from the ocean. Results, Under the two climate change scenarios, current climates across most of California and Nevada will shrink greatly in extent, and the climates of the highest peaks will disappear from this region. Expanding and novel climates are projected for the Central Valley. Current temperature isoclines are projected to move up to 4.9 km year,1 in flatter regions, but substantially slower in mountainous areas because of steep local topoclimate gradients. In the San Francisco Bay Area, climate diversity within currently protected areas increases with reserve size and proximity to the ocean (the latter because of strong coastal climate gradients). However, by 2100 of almost 500 protected areas (>100 ha), only eight of the largest are projected to experience temperatures within their currently observed range. Topoclimate variability will further increase the range of conditions experienced and needs to be incorporated in future analyses. Main Conclusions, Spatial heterogeneity in climate, from mesoclimate to topoclimate scales, represents an important spatial buffer in response to climate change, and merits increased attention in conservation planning. [source] BDNF variability in opioid addicts and response to methadone treatment: preliminary findingsGENES, BRAIN AND BEHAVIOR, Issue 5 2008R. De Cid Brain-derived neurotrophic factor (BDNF) signaling pathways have been shown to be essential for opioid-induced plasticity. We conducted an exploratory study to evaluate BDNF variability in opioid addict responders and nonresponders to methadone maintenance treatment (MMT). We analyzed 21 single nucleotide polymorphisms (SNPs) across the BDNF genomic region. Responders and nonresponders were classified by means of illicit opioid consumption detected in random urinalysis. Patients were assessed by a structured interview (Psychiatric Research Interview for Substance and Mental Disorders (PRISM)-DSM-IV) and personality was evaluated by the Cloninger's Temperament and Character Inventory. No clinical, environmental and treatment characteristics were different between the groups, except for the Cooperativeness dimension (P < 0.001). Haplotype block analysis showed a low-frequency (2.7%) haplotype (13 SNPs) in block 1, which was more frequent in the nonresponder group than in the responder group (4/42 vs. 1/135; Pcorrected = 0.023). Fine mapping in block 1 allows us to identify a haplotype subset formed by only six SNPs (rs7127507, rs1967554, rs11030118, rs988748, rs2030324 and rs11030119) associated with differential response to MMT (global P sim = 0.011). Carriers of the CCGCCG haplotype had an increased risk of poorer response, even after adjusting for Cooperativeness score (OR = 20.25 95% CI 1.46,280.50, P = 0.025). These preliminary results might suggest the involvement of BDNF as a factor to be taken into account in the response to MMT independently of personality traits, environmental cues, methadone dosage and psychiatric comorbidity. [source] LOOKING AT THE "POPULATION PROBLEM" THROUGH THE PRISM OF HETEROGENEITY: WELFARE AND POLICY ANALYSES,INTERNATIONAL ECONOMIC REVIEW, Issue 3 2008C. Simon Fan Upon introducing heterogeneity and dynamics into a model of the demand for children, a problem of optimal population is defined and analyzed. It is shown that from the perspective of social welfare, better-educated individuals produce too few children while less-educated individuals produce too many children and all individuals invest too little in the education of their children. The impact of several policy tools geared at addressing the "population problem" is investigated, in particular how child allowances and other tax-subsidy policies can be harnessed to enhance welfare, and how and why early childhood education programs can mitigate the "population problem." [source] Dynamic reduction of a CH4/air chemical mechanism appropriate for investigating vortex,flame interactionsINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 4 2007Shaheen R. Tonse This paper describes two methods, piecewise reusable implementation of solution mapping (PRISM) and dynamic steady-state approximation (DYSSA), in which chemistry is reduced dynamically to reduce the computational burden in combustion simulations. Each method utilizes the large range in species timescales to reduce the dimensionality to the number of species with slow timescales. The methods are applied within a framework that uses hypercubes to partition multidimensional chemical composition space, where each chemical species concentration, plus temperature, is represented by an axis in space. The dimensionality of the problem is reduced uniquely in each hypercube, but the dimensionality of chemical composition space is not reduced. The dimensionality reduction is dynamic and is different for different hypercubes, thereby escaping the restrictions of global methods in which reductions must be valid for all chemical mixtures. PRISM constructs polynomial equations in each hypercube, replacing the chemical kinetic ordinary differential equation (ODE) system with a set of quadratic polynomials with terms related to the number of species with slow timescales. Earlier versions of PRISM were applied to smaller chemical mechanisms and used all chemical species concentrations as terms. DYSSA is a dynamic treatment of the steady-state approximation and uses the fast,slow timescale separation to determine the set of steady-state species in each hypercube. A reduced number of chemical kinetic ODEs are integrated rather than the original full set. PRISM and DYSSA are evaluated for simulations of a pair of counterrotating vortices interacting with a premixed CH4/air laminar flame. DYSSA is sufficiently accurate for use in combustion simulations, and when relative errors are less than 1.0%, speedups on the order of 3 are observed. PRISM does not perform as well as DYSSA with respect to accuracy and efficiency. Although the polynomial evaluation that replaces the ODE solver is sufficiently fast, polynomials are not reused sufficiently to enable their construction cost to be recovered. © 2007 Wiley Periodicals, Inc. 39: 204,220, 2007 [source] Computational economy improvements in PRISMINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 9 2003Shaheen R. Tonse The Piecewise Reusable Implementation of Solution Mapping (PRISM) procedure is applied to reactive flow simulations of (9-species) H2 + air combustion. PRISM takes the solution of the chemical kinetic ordinary differential equation system and parameterizes it with quadratic polynomials. To increase the accuracy, the parameterization is done piecewise, by dividing the multidimensional chemical composition space into hypercubes and constructing polynomials for each hypercube on demand. The polynomial coefficients are stored for subsequent repeated reuse. Initial cost of polynomial construction is expensive, but it recouped as the hypercube is reused, hence computational gain depends on the degree of hypercube reuse. We present two methods that help us to identify hypercubes that will ultimately have high reuse, this being accomplished before the expense of constructing polynomials has been incurred. One method utilizes the rate of movement of the chemical trajectory to estimate the number of steps the trajectory would make through the hypercube. The other method defers polynomial construction until a preset threshold of reuse has been met; an empirical method which, nevertheless, produces a substantial gain. The methods are tested on a 0-D chemical mixture and reactive flow 1-D and 2-D simulations of selected laminar and turbulent H2 + air flames. The computational performance of PRISM is improved by a factor of about 2 for both methods. © 2003 Wiley Periodicals, Inc., Int J Chem Kinet 35: 438,452, 2003 [source] Radar-guided interpolation of climatological precipitation dataINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 2 2009Arthur T. DeGaetano Abstract A refined approach for interpolating daily precipitation accumulations is presented, which combines radar-based information to characterize the spatial distribution and gross accumulation of precipitation with observed daily rain-gauge data to adjust for spatially varying errors in the radar estimates. Considering the rain gauge observations to be true values at each measurement location, daily radar errors are calculated at these points. These errors are then interpolated back to the radar grid, providing a spatially varying daily adjustment that can be applied across the radar domain. In contrast to similar techniques that are employed at hourly intervals to adjust radar-rainfall estimates operationally, this refined approach is intended to provide high-spatial-resolution precipitation data for climatological purposes, such as drought and environmental monitoring, retrospective impact analyses, and (when time series of sufficient length become available) assessment of temporal precipitation variations at high-spatial-resolution. Compared to the Multisensor Precipitation Estimators (MPEs) used operationally, the refined method yields lower cross-validated interpolation errors regardless of season or daily precipitation amount. Comparisons between cross-validated radar estimates aggregated to monthly totals with operational (non-cross-validated) Parameter-elevation Regressions on Independent Slopes Model (PRISM) precipitation estimates are also favourable. The new method provides a radar-based alternative to similar climatologies based on the spatial interpolation of gauge data alone (e.g. PRISM). Copyright © 2008 Royal Meteorological Society [source] Interrater reliability of the Psychiatric Research Interview for Substance and Mental Disorders in an HIV-infected cohort: experience of the National NeuroAIDS Tissue ConsortiumINTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue 3 2006S. Morgello Abstract The interrater reliability of the Psychiatric Research Interview for Substance and Mental Disorders (PRISM) was assessed in a multicentre study. Four sites of the National NeuroAIDS Tissue Consortium performed blinded reratings of audiotaped PRISM interviews of 63 HIV-infected patients. Diagnostic modules for substance-use disorders and major depression were evaluated. Seventy-six per cent of the patient sample displayed one or more substance-use disorder diagnoses and 54% had major depression. Kappa coefficients for lifetime histories of substance abuse or dependence (cocaine, opiates, alcohol, cannabis, sedative, stimulant, hallucinogen) and major depression ranged from 0.66 to 1.00. Overall the PRISM was reliable in assessing both past and current disorders except for current cannabis disorders when patients had concomitant cannabinoid prescriptions for medical therapy. The reliability of substance-induced depression was poor to fair although there was a low prevalence of this diagnosis in our group. We conclude that the PRISM yields reliable diagnoses in a multicentre study of substance-experienced, HIV-infected individuals. Copyright © 2006 John Wiley & Sons, Ltd. [source] Using the PRISM to Compare the Explanatory Value of General and Role-Contextualized Trait RatingsJOURNAL OF PERSONALITY, Issue 6 2007Dustin Wood ABSTRACT In an earlier work (Wood & Roberts, 2006), the Personality and Role Identity Structural Model (PRISM) was proposed as a model for organizing the relations between diverse self-perceptions, with a person's general identity ("how I am in general") organized above diverse role identities (e.g., "how I am as an employee"), which in turn is organized above role-specific behaviors and experiences (e.g., typical interactions with coworkers). In the present article, I argue that despite the fact that role trait measures are often much more related to role behaviors than general trait measures in cross-sectional analyses, general trait measures better capture the dispositional causes of a person's role behavior. In support of this, a brief study is presented illustrating how general traits may be better predictors than role-contextualized trait ratings of the evolution of an individual's experiences or behaviors within a given context. Finally, I contend that the basic framework of the PRISM, where a person's behaviors and identities within multiple contexts are assessed simultaneously and longitudinally alongside general personality ratings, is necessary to make strong statements concerning the nature of the relationships between personality traits and role experiences. [source] Circulating levels of KL-6 in acute respiratory distress syndrome sepsis or traumatic brain injury in critically ill childrenPEDIATRIC PULMONOLOGY, Issue 8 2006George Briassoulis MD Abstract KL-6 is a high molecular weight glycoprotein that is expressed on the apical borders of normal secretary alveolar epithelial cells. The aim of our study was to elucidate the potential role of circulating levels of KL-6, related to C-reacting protein (CRP), disease severity (PRISM, TISS), length of stay (LOS) or mechanical ventilation (LOMV), and outcome, in children with acute respiratory distress syndrome (ARDS), sepsis, or traumatic brain injury (TBI). KL-6 concentrations were monitored using solid phase sandwich enzyme-linked immunosorbent assay in plasma of nine patients with ARDS and compared to nine patients with TBI, nine with sepsis, and nine ventilated patients with cancer of matched illness severity on days 1, 3, 5, 7, and 10. Initial respiratory/ventilatory parameters (oxygenation index, plateau pressures) were recorded for ARDS patients. Patients with ARDS had higher early plasma levels of KL-6 (956,±,400 U/ml), as compared to patients with TBI (169,±,9 U/ml), sepsis (282,±,81 U/ml), and ventilated controls (255,±,40 U/ml). Significant correlations were demonstrated between plasma KL-6 concentration and oxygenation index, PaO2: FiO2 ratio, LOS and LOMV, but not with CRP or PRISM. Only in patients with ARDS, plasma KL-6 levels were higher in non-survivors than survivors (P,<,0.03). Plasma KL-6 levels have possible prognostic significance and may provide a useful marker for ARDS in critically ill children. Pediatr Pulmonol. 2006; 41: 790,795. © 2006 Wiley-Liss, Inc. [source] Severe upper airway obstruction in the tropics requiring intensive carePEDIATRICS INTERNATIONAL, Issue 1 2001Pwk Chan Background: The clinical profile of severe upper airway obstruction, a challenging acute pediatric emergency, has not been extensively documented in the developing nations of the tropics. Methods: The diagnostic categories, severity of illness and outcome from 63 episodes of severe upper airway obstruction in 56 children admitted to the Pediatric Intensive Care Unit between January 1994 and December 1999 were reviewed. Outcome variables studied included requirement for ventilation, mortality and complications. Severity of illness was determined with the Pediatric Risk of Mortality (PRISM) II score. Results: Viral croup (29%) was the most common diagnosis, followed by mediastinal malignancy (13%), bacterial tracheitis (11%) and Pierre Robin syndrome (11%). There were no admissions for acute epiglottitis. Thirty episodes (48%) required ventilation for a median duration of 4.0 days. Bacterial tracheitis (100%) and subglottic stenosis (100%) were the most likely diagnoses requiring ventilation. Difficulty in intubation was encountered in 13 episodes (43%) involving, in particular, patients with bacterial tracheitis (83%; P=0.006). Only two patients required a tracheostomy. The overall mortality was 11%. The PRISM score for all categories was generally low (mean 10.3~1.0; median 9.0). Non-survivors had a significantly higher PRISM II score than survivors (27.4~9.7 vs 8.1~4.9, respectively; P=0.002) and were more likely to include children with bacterial tracheitis and mediastinal malignancy. Conclusions: There is marked heterogeneity in the causes of upper airway obstruction in the tropics with viral croup remaining the most common. A significant proportion required ventilation, but outcome is generally favorable, except in those with bacterial tracheitis and mediastinal malignancy. [source] REFERENCE AND INTENTIONALITY: REFLECTIONS ON WETTSTEIN'S MAGIC PRISMANALYTIC PHILOSOPHY, Issue 1 2006Robin Jeshion First page of article [source] PRISM: Mounting a community-randomised trial.AUSTRALIAN AND NEW ZEALAND JOURNAL OF PUBLIC HEALTH, Issue 5 2004Establishing partnerships with local government This paper describes initial partnership development in PRISM (Program of Resources, Information and Support for Mothers), a community-randomised trial to improve maternal health in the first year after birth conducted in Victoria in the period 1998,2003. First, we discuss the principles underpinning community recruitment methods in PRISM that guided both our initial approaches to, and our continuing relationships with, communities. Second, we outline the strategies used to recruit communities and to establish the groundwork for ongoing partnerships over the projected six years of the study. [source] Diagnosing comorbidity: concepts, criteria, and methodsACTA NEUROPSYCHIATRICA, Issue 1 2004S. Samet Background:, The clinical and etiologic implications of comorbid psychiatric and substance-use disorders are relevant across countries and cultures. The DSM-IV now places greater emphasis on the clinical and research utility of the substance-induced disorders classification, and clarifies several important diagnostic issues specific to primary and substance-induced disorders. However, no research consensus exists over the core problem of identifying and differentiating the drug and alcohol intoxication and withdrawal symptoms that can mimic psychiatric symptoms in heavy drinkers and drug users. Objective:, To investigate how various diagnostic instruments have measured comorbid psychiatric and substance-use disorders and how each instrument operationalizes the DSM-IV classification. Method:, We review the evolution of the concept of comorbidity beginning with its formalization as the ,primary,secondary' distinction in the Feighner Criteria. We address the ,organic,non-organic' distinction found in the RDC, DSM-III, and DSM-III-R; and finally, review the ,primary' and ,substance-induced' categories of DSM-IV, DSM-IV-TR and ICD-10. We describe how these distinctions have been operationalized in widely used diagnostic instruments. Conclusion:, Further understanding of these classifications and the rela-tionship of co-occurring psychiatric and substance disorders can be accom-plished with the range of available measures, particularly the Psychiatric Research Interview for Substance and Mental Disorders (PRISM), which reliably utilizes and refines DSM-IV classification distinctions. [source] Description of the Structure and Properties of Atactic Polystyrene Melt Using Integral Equation TheoryCHINESE JOURNAL OF CHEMISTRY, Issue 12 2007Lei ZHAO Abstract The polymer reference interaction site model (PRISM) integral equation theory was used to describe the structure and thermodynamic properties of atactic polystyrene (aPS) melt, in which the monomer of aPS is represented with an eight-site model to characterize its microstructure. The intramolecular structure factors needed in the PRISM calculations were obtained from single chain MD simulations. The calculated results indicate that the results by the integral equation method agrees well with experiments, and can reflect the fine microscopic structure of real aPS melt. This work shows that the PRISM theory is a powerful tool for investigating the structure and properties of complex polymers. [source] Isolation and identification of Alicyclobacillus acidocaldarius by 16S rDNA from mango juice and concentrateINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 7 2005Pieter A. Gouws Summary In this study we investigate the spoilage of ultra high temperature UHT mango juice as well as a carbonated fruit juice blend to identify organisms contributing to the spoilage. The mango concentrate, the final product, as well as the other ingredients used during manufacturing, were tested for the presence of Alicyclobacillus by polymerase chain reaction (PCR) and sequencing analyses. Microbiological examination of the mango pureé and spoiled fruit juices, using YSG agar [yeast extract 2 g, glucose 1 g, soluble starch 2 g, pH 3.7 (adjust with 2N H2SO4), H2O 1000 mL, bacto agar 15 g] incubated at 55 °C, detected sporeforming, acid dependent and thermotolerant bacteria. The hyper variable region of the 16S rDNA was amplified. The nucleotide sequence of the PCR fragments was determined using the ABI Prism 310 automated DNA sequencer and the collected sequencing data were analysed and compared with the non-redundant database using NCBI-BLAST. Alicyclobacillus acidocaldarius were isolated and identified by 16S rDNA gene sequences analyses. The results indicated that the mango purče, as well as the final product of mango juice and the fruit juice blend, were positive for Alicyclobacillus. The preventative measures of low pH, pasteurization of mango juice and the subsequent use of aseptic packaging were not regarded as sufficient to prevent the outgrowth of Alicyclobacillus spoilage organisms. [source] Unclaimed Colonies: Anglo-Greek Identities Through the Prism of the Dilessi/Marathon Murders (1870)JOURNAL OF HISTORICAL SOCIOLOGY, Issue 2 2002Rodanthi Tzanelli This paper examines the Anglo-Greek dialogue on Greek and British European identities following the Dilessi/Marathon Murders, a case of kidnapping and murder of three upper class Britons by Greek brigands, which became the European cause célčbre of the 1870s. It focuses on British and Greek narratives of brigandage and uses them to provide some insight into the ways both sides conceptualised modernity. The uses of the Greek, Irish and Scottish past and present in this dialogue formed a discourse in which history, imperialism and romanticism were woven altogether. This paper argues that these intertwined ideas and processes were complicit in the formation of modern British and Greek national identities. [source] The increase in the frequency of MICA gene A6 allele in oral squamous cell carcinomaJOURNAL OF ORAL PATHOLOGY & MEDICINE, Issue 6 2002Liu Chung-Ji Abstract Background: Oral squamous cell carcinoma (OSCC) was reported to be associated with immune function. The MICA (MHC class I chain-related gene A) is expressed by keratinocytes and other epithelial cells, and its encoded protein interacts with ,/, T cells localized in submucosa. The MICA also influences the heat shock protein function. We speculated that the alterations of MICA might influence the pathogenesis of OSCC through the aberration in presenting tumor antigens or heat shock protein. MICA gene has a triplet repeat (GCT) polymorphism in the transmembrane domain, resulting in five distinctive allelic patterns. Methods: We analysed this MICA polymorphism in 67 OSCC patients and 351 randomly selected unrelated controls. By using the ABI Prism 377,18 DNA sequencer (Applied Biosystems, Foster City, CA, USA) to analyse the sample DNA PCR products. The number of micro-satellite repeats was estimated with Genescan 672 software (Applied Biosystems) with a standard size marker of GS-350 TAMRA (N,N,N,N-tetramethyl-6-carbohydroxyl rhodamine; Applied Biosystems). Results: The phenotype frequency of allele A6 of MICA in subjects with OSCC was significantly higher than that in controls (RR = 3.46, 95% CI = 1.73,6.94, P = 0.0002), as was the frequency of allele (RR = 2.64, 95% CI = 1.39,5.02, P = 0.002). Conclusion: The results suggest that allele A6 in MICA might confer the risk of OSCC. [source] ChemInform Abstract: La8Br7Ni4: Ribbons of Ni Hexagons in Condensed La6 Trigonal Prisms.CHEMINFORM, Issue 10 2009Chong Zheng Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] La4Br2Al5 and Ce4Br2Ga5: Three-Dimensional Metal Networks Embedded in Condensed Ln6 Trigonal Prisms.CHEMINFORM, Issue 12 2004Chong Zheng Abstract For Abstract see ChemInform Abstract in Full Text. [source] Gd3Pt4In12 and Tb3Pt4In12 , New Ternary Indides with Condensed Distorted [PtIn6] Trigonal Prisms.CHEMINFORM, Issue 50 2002Ute Ch. Abstract For Abstract see ChemInform Abstract in Full Text. [source] Corporate Governance in the Russian Federation: the relevance of the OECD Principles on shareholder rights and equitable treatmentCORPORATE GOVERNANCE, Issue 2 2001Fianna Jesover Despite progress in developing extensive legislation and regulations, there is still a long way to go before the standards of corporate governance in Russia will instil widespread confidence in investors. The emphasis is now on their implementation and enforcement by the state and private sector institutions. Transparent, equitable rules and predictable enforcement mechanisms are necessary to make the Russian economy attractive to both domestic and foreign investors, and enhance public confidence in the overall reform process. This paper uses the first two chapters of the OECD Principles of Corporate Governance on shareholder rights and their equitable treatment and looks through their prism at the Russian corporate governance condition. [source] From Soviet Modernization to Post,Soviet Transformation: Understanding Marriage and Fertility Dynamics in UzbekistanDEVELOPMENT AND CHANGE, Issue 3 2003Victor Agadjanian In this article we analyse the dynamics of marriage and childbearing in Uzbekistan through the prism of the recent socioeconomic and political history of that country. After becoming an independent nation in 1991, Uzbekistan abandoned the Soviet modernization project and aspired to set out on a radically different course of economic, social, and political development. We argue, however, that not only independence but also the preceding period of perestroika reforms (1985,91) had a dramatic effect on social conditions and practices and, consequently, the demographic behaviour of the country's population. Using data from the 1996 Uzbekistan Demographic and Health Survey we apply event,history analysis to examine changes in the timing of entry into first marriage, first and second births over four periods: two periods of pre,perestroika socialism, the perestroika years, and the period since independence. We investigate the factors that influenced the timing of these events in each of the four periods among Uzbeks, the country's eponymous and largest ethnic group, and among Uzbekistan's urban population. In general, our results point to a dialectic combination of continuity and change in Uzbekistan's recent demographic trends, which reflect the complex and contradictory nature of broader societal transformations in that and other parts of the former Soviet Union. [source] Structure Comparison of Early and Late Lanthanide(III) Homodinuclear Macrocyclic Complexes with the Polyamine Polycarboxylic Ligand H8OHECEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 19 2004Ulrike A. Böttger Abstract The solid-state structures of two new homodinuclear chelate complexes with the late lanthanide(III) ions Yb and Lu, [Na2(Yb2OHEC)].14.5H2O (1), and [Na2(Lu2OHEC)].14.5H2O (2) (H8OHEC = 1,4,7,10,14,17,20,23-octaazacyclohexacosane- 1,4,7,10,14,17,20,23-octaacetic acid), have been determined by X-ray crystal structure analysis. Each lanthanide(III) ion is coordinated by eight donor atoms of the ligand and the geometry of the coordination polyhedron approaches a bicapped trigonal prism. These structures are compared with those of the homodinuclear chelate complexes with the same ligand and the mid to early lanthanide(III) ions Gd, Eu, La and also Y. A distinctive structural change occurs across the lanthanide series. The centrosymmetric mid to early lanthanide(III) complexes are all ninefold-coordinated in a capped square antiprismatic arrangement with a water molecule coordinated in a prismatic position. This structure is maintained in aqueous solution, together with an asymmetric minor isomer. The late lanthanide(III) OHEC complexes not only lack the inner-sphere water, but the change of coordination sphere also results in a loss of symmetry of the whole complex molecule. The observed change of coordination mode and number of the lanthanide ion may offer a geometric model for the isomerization process in eight- and ninefold-coordinated complex species that are isomers in a possible coordination equilibrium observed by NMR in aqueous solution. This model may also explain the intramolecular rearrangements necessary during water exchange in the inner coordination sphere of the complex [(Gd2OHEC)(H2O)2]2, through a slow dissociative mechanism. Protonation constants of the H8OHEC ligand and complex formation constants of this ligand with GdIII, CaII, CuII and ZnII have been determined by solution thermodynamic studies. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Synthesis and Microstructural Characterisation of Two New One-Dimensional Members of the (A3NiMnO6),(A3Mn3O9), Homologous Series (A = Ba, Sr)EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2003María Hernando Abstract Two new members of the one-dimensional (A3NiMnO6),(A3Mn3O9), homologous series, with the compositions (Sr0.75Ba0.25)5NiMn3O12 and Sr9Ni2Mn5O21, have been synthesised. Their structures can each be described as a hexagonal array of infinite one-dimensional chains of face-sharing polyhedra, running parallel to the c axis and separated by the Sr/Ba cations. The structure of (Sr0.75Ba0.25)5NiMn3O12, which constitutes the (, = 3, , = 2) member of the series, is made up of three face-sharing octahedra linked by one trigonal prism. For Sr9Ni2Mn5O21 (, = 2, , = 1) the sequence of polyhedra along the chains corresponds to a motif consisting of two octahedra,one trigonal prism,three octahedra,one trigonal prism. The manganese atoms occupy the octahedral sites in both phases, while the Ni2+ cations are distributed in the trigonal-prismatic sites in a disordered way. Only a small fraction of these (close to 20%) is located at the centres of the trigonal prisms, 80% being displaced towards the rectangular faces of the polyhedra and giving rise to a square-planar-like coordination. Both oxides present twinned microstructures, as evidenced by SAED and HREM. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003) [source] Comparison of methods to model the gravitational gradients from topographic data basesGEOPHYSICAL JOURNAL INTERNATIONAL, Issue 3 2006Christopher Jekeli SUMMARY A number of methods have been developed over the last few decades to model the gravitational gradients using digital elevation data. All methods are based on second-order derivatives of the Newtonian mass integral for the gravitational potential. Foremost are algorithms that divide the topographic masses into prisms or more general polyhedra and sum the corresponding gradient contributions. Other methods are designed for computational speed and make use of the fast Fourier transform (FFT), require a regular rectangular grid of data, and yield gradients on the entire grid, but only at constant altitude. We add to these the ordinary numerical integration (in horizontal coordinates) of the gradient integrals. In total we compare two prism, two FFT and two ordinary numerical integration methods using 1, elevation data in two topographic regimes (rough and moderate terrain). Prism methods depend on the type of finite elements that are generated with the elevation data; in particular, alternative triangulations can yield significant differences in the gradients (up to tens of Eötvös). The FFT methods depend on a series development of the topographic heights, requiring terms up to 14th order in rough terrain; and, one popular method has significant bias errors (e.g. 13 Eötvös in the vertical,vertical gradient) embedded in its practical realization. The straightforward numerical integrations, whether on a rectangular or triangulated grid, yield sub-Eötvös differences in the gradients when compared to the other methods (except near the edges of the integration area) and they are as efficient computationally as the finite element methods. [source] The Four Faces of Institutionalism: Public Policy and a Pluralistic PerspectiveGOVERNANCE, Issue 4 2000Simon Reich Contending conceptions of the "new" institutionalism claim to offer approaches that can develop generalizable social scientific theories of behavior. This article challenges that proposition, arguing that contingencies exist in which specific forms of institutionalism are best suited to addressing particular types of questions. Viewed through the prism of public policy, it develops the argument that ,policy dictates politics.' It suggests that four variants of institutionalism (historical, new economic, normative, and billiard ball) are each systematically most appropriate to examine the issues in the policy domains of redistribution, regulation, modernization, and liberalization, respectively. [source] Mechanisms Controlling Crystal Habits of Gold and Silver ColloidsADVANCED FUNCTIONAL MATERIALS, Issue 7 2005C. Lofton Abstract Examples of gold and silver anisotropic colloids, such as prisms and rods, have appeared in the literature for many years. In most cases, the morphologies of these thermodynamically unfavorable particles have been explained by the particular reaction environment in which they were synthesized. The mechanisms used to explain the growth generally fall into two categories, one in which chemically adsorbed molecules regulate the growth of specific crystal faces kinetically, and the other where micelle-forming surfactants physically direct the shape of the particle. This paper raises questions about the growth of anisotropic metal colloids that the current mechanisms cannot adequately address, specifically, the formation of multiple shapes in a single homogeneous reaction and the appearance of similar structures in very different synthesis schemes. These observations suggest that any growth mechanism should primarily take into consideration nucleation and kinetics, and not only thermodynamics or physical constrictions. The authors suggest an alternative mechanism where the presence and orientation of twin planes in these face-centered cubic (fcc) metals direct the shape of the growing particles. This explanation follows that used for silver halide crystals, and has the advantage of explaining particle growth in many synthesis methods. In this mechanism, twin planes generate reentrant grooves, favorable sites for the attachment of adatoms. Shape and structural data are presented for gold and silver particles synthesized using several different techniques to support this new model. Triangular prisms are suggested to contain a single twin plane which directs that growth of the initial seed in two dimensions, but limits the final size of the prism. Hexagonal platelets are suggested to contain two parallel twin planes that allow the fast growing edges to regenerate one another, allowing large sizes and aspect ratios to form. Rods and wires were found to have a fivefold symmetry, which may only allow growth in one dimension. It is expected that a superior mechanistic understanding will permit shape-selective synthesis schemes to be developed. [source] Tidal Barrages and BirdsIBIS, Issue 2006NIGEL A. CLARK This paper reviews the main effects that building tidal power barrages would have on the bird populations using Britain's estuaries. The changes in the tidal prism that would occur after a tidal power barrage is built are discussed in the context of their effect on the ecology of the estuary. Three main issues are discussed; the effect of changes in size and nature of the intertidal areas of the estuary, effects on saltmarshes, and the displacement of birds at closure. Recently, tidal stream technologies have been developed which are individually likely to have small effects on birds. However the cumulative effects of large scale tidal stream arrays need to be investigated. Finally, the effects of tidal barrages are put in the context of Britain's energy policy and the need to reduce greenhouse gas emissions. Should tidal power barrages be considered in the future, there will be a need for strategic assessments to be used to select sites that maximize the energy produced while minimizing the impacts on bird populations. [source] The impact of EU accession on Turkish industrial relations and social dialogueINDUSTRIAL RELATIONS JOURNAL, Issue 3 2008Engin Yildirim ABSTRACT This article examines whether the European Union membership process is transforming the ,deep structure' of Turkish industrial relations. We make an attempt to illustrate this through the prism of Turkish experience in social dialogue regarded as an indispensable tool of the European social model. Turkish industrial relations is characterised by restrictive labour laws, employer hostility to unionisation, a large informal economy and labour market, and strong state intervention, which have historically constituted the main elements of ,the deep structure' of Turkish industrial relations. In procedural terms, the institutions for social dialogue have been established but the influence of the social partners is limited because of the dominance of the state and the weakness of labour. The existing attempts at developing social dialogue rest on shaky foundations emanating mostly from the state's and employers' disrespect of basic labour rights. [source] Zinc Oxide Microstructures: Zinc Oxide Microtowers by Vapor Phase Homoepitaxial Regrowth (Adv. Mater.ADVANCED MATERIALS, Issue 8 20098/2009) Simultaneous axial and radial epitaxies can be achieved by growing ZnO microtowers by repeating a growth cycle several times, report Zhengwei Pan and co-workers on p. 890. The as-grown ZnO microtowers display a preferential growth habit of hexagonal prism,dihexagonal pyramid. Some rare or new growth habits such as dihexagonal prism,dihexagonal pyramid, hexagonal prism,trihexagonal pyramid and dihexagonal prism,trihexagonal pyramid (as shown on the cover) have also been identified. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||